PRAM stands for Parallel Random Access Machine, which is an abstract machine for designing the algorithms applicable to parallel computers. It eliminates the focus on miscellaneous issues such as synchronization and communication, but lets designer think explicitly about the exploitation of concurrency.

The operation of a synchronous PRAM can result in simultaneous access by multiple processors to the same location in shared memory. There are several variants of our PRAM model, depending on whether such simultaneous access is permitted or prohibited. As accesses can be reads or writes, there are four possibilities:

1. Exclusive Read Exclusive Write
2. Concurrent Read Exclusive Write
3. Exclusive Read Concurrent Write
4. Concurrent Read Concurrent Write

See also

• Lock-free and wait-free algorithms